Apparatus and Method for Chilling or Freezing Objects Utilizing a Rotary Drum Having Prominences Formed on an Inner Surface Thereof

ABSTRACT

In an apparatus and method for chilling or freezing objects, an interior surface of a rotating drum includes recesses formed between prominences extending inwardly from the interior surface. One or more liquid CO 2  nozzles inject solid CO 2  towards the interior surface. The injected snow replenishes a depth of solid CO 2  in empty or partially empty recesses and/or provides a fresh layer of solid CO 2  on top of the objects. Because the interior surface is made of polyethylene and the depth of solid CO 2  is replenished in empty or partially empty recesses, the product/drum sticking problem experienced by conventional apparatuses and methods is reduced or avoided. Optionally, the CO 2  snow is injected into empty or partially empty recesses by at least one first liquid CO 2  nozzle and is deposited on top of the objects by at least one second liquid CO 2  nozzle so that each opposing surface of the object is in direct contact with solid CO 2 .

BACKGROUND

Many food products must be chilled below 40° F. prior to shipment.Sometimes this is achieved by mixing the product with solid CO₂ (eitherdry ice “snow” or dry ice pellets) in a stainless steel drum. However,the interior surface of the stainless steel drum becomes so cold thatmoist products can stick to the surface, resulting in damaged product,un-recovered product, and disruption of the flow of product through thedrum.

To solve this problem, many prior art references utilize a small amountof water that forms an ice layer on the stainless steel surface. See,e.g., U.S. Pat. No. 5,220,812 to Palbiski et al. and U.S. Pat. No.5,603,567 to Peacock. Others position the CO₂ nozzles so that CO₂ snowis only administered onto the pieces of food being cooled. See, e.g.,U.S. Pat. No. 6,497,106 to Lang et al. Either method fails to provideeffective two-sided exposure of the object to CO₂ snow and therebyextends the amount of time it takes to chill the product.

Thus, there is a need in the art for a method of cooling food with solidCO₂ in a rotating drum without incurring too much product sticking.

SUMMARY

There is provided an apparatus for chilling or freezing objects, theapparatus comprising a rotatable drum defining an enclosure having aninterior surface, an inlet at one end of the drum, an outlet at anopposing end of the drum, and at least two CO2 nozzles located withinthe enclosure, at least one CO2 nozzle positioned horizontally and atleast one CO2 nozzle positioned vertically, the interior surface beingpolyethylene having prominences thereon, wherein the prominences are notdirectional vanes.

There is also provided a method for chilling or freezing objects, themethod comprising the following steps. The above-provided apparatus isprovided. CO₂ snow is ejected from the at least one CO₂ nozzlepositioned horizontally to produce a blanket of CO₂ snow on the interiorsurface between the prominences. The object to be chilled or frozen isintroduced into the inlet of the drum. The drum is rotated. CO₂ snow isejected from the at least one CO₂ nozzle positioned vertically toproduce a blanket of CO₂ snow on the object. The object is removed fromthe outlet of the drum.

There is also provided another apparatus for chilling or freezingobjects, the apparatus comprising a rotatable drum defining an enclosurehaving an interior surface, an inlet at one end of the drum, an outletat an opposing end of the drum, one or more liquid CO₂ nozzles disposedin an interior of the drum each one of which is adapted to inject astream of solid CO₂ into the enclosure towards the interior surface. Theinterior surface of the drum is comprised of polyethylene havingprominences molded into the polyethylene. Portions of the interiorsurface in between prominences form recesses relative to the prominencesthat are adapted and configured to retain a depth of solid CO₂. Theprominences are not directional vanes.

There is also provided another method for chilling or freezing objects,comprising the following steps. The above apparatus is provided. Thedrum is rotated. The objects are introduced into the interior the drum.A stream of solid CO₂ is injected into the enclosure towards theinterior surface from one or more liquid CO₂ nozzles, wherein the solidCO₂ is deposited in the recesses and/or on top of the objects. Theobjects are removed from the outlet of the drum.

The apparatus or method may include any one or more of the followingaspects:

-   -   the apparatus further comprises directional vanes on the        interior surface.    -   the prominences extend approximately 0.25 to 1 inches from the        interior surface.    -   the apparatus further comprises directional vanes on the        interior surface.    -   said at least two liquid CO₂ nozzles comprise at least one first        liquid CO₂ nozzle and at least one second liquid CO₂, each of        said at least one first liquid CO₂ nozzles being disposed in an        interior of the drum and being adapted, configured, and oriented        to provide a first stream of solid CO₂ towards a first angular        position on the inner surface, each of said at least one second        liquid CO₂ nozzle being disposed in the drum interior and being        adapted, configured, and oriented to provide a second stream of        solid CO₂ towards a second angular position on the inner        surface, and the first angular position is between 70-110°        and/or 250-290° with respect to vertical and the second angular        position is between 160-200° with respect to vertical.    -   the apparatus further comprises directional vanes on the        interior surface.    -   the prominences extend approximately 0.25 to 1 inches from the        interior surface.    -   the apparatus further comprises directional vanes on the        interior surface.    -   said at least two liquid CO₂ nozzles comprise at least one first        liquid CO₂ nozzle and at least one second liquid CO₂, each of        said at least one first liquid CO₂ nozzles being disposed in an        interior of the drum and injects a first stream of solid CO₂        towards a first angular position on the inner surface, each of        said at least one second liquid CO₂ nozzle being disposed in the        drum interior and injects a second stream of solid CO₂ towards a        second angular position on the inner surface, and the first        angular position is between 70-110° and/or 250-290° with respect        to vertical and the second angular position is between 160-200°        with respect to vertical.    -   the first stream(s) deposits a fresh layer of solid CO₂ in the        recesses and the second stream(s) deposits solid CO₂ on top of        the objects tumbling at or adjacent to a bottom of the drum.    -   the objects are food products.    -   the food products are meat products.

BRIEF DESCRIPTION OF THE DRAWINGS

For a further understanding of the nature and objects of the presentinvention, reference should be made to the following detaileddescription, taken in conjunction with the accompanying drawings, inwhich like elements are given the same or analogous reference numbersand wherein:

FIG. 1 is a cross-sectional, front (inlet) view of an embodiment of thedisclosed chilling or freezing apparatus taken along an axis of therotating drum that illustrates alternative positions and orientationsfor the CO₂ snow nozzles.

FIG. 2 is a side, elevation view of another embodiment of the disclosedchilling or freezing apparatus that includes directional vanes but whichomits the prominences for the sake of clarity;

FIG. 3 is an isometric, schematic view of the rotating drum of thedisclosed chilling or freezing apparatus;

FIG. 4 is an elevation side view of one embodiment of the interiorsurface of the rotating drum;

FIG. 5 is an elevation side view of a second embodiment of the interiorsurface of the rotating drum; and

FIG. 6 is an elevation side view of a third embodiment of the interiorsurface of the rotating drum.

DESCRIPTION OF PREFERRED EMBODIMENTS

Disclosed is an apparatus and method for chilling or freezing objects.While the preferred embodiments are disclosed with respect to foodproducts, and preferably with respect to meat products, such as chicken,beef, and turkey parts, the disclosed apparatus and method may also beutilized with any object that requires chilling or freezing, such asseafood, produce, golf ball centers and insulated wire scrap.

In the inventive apparatus and method, an interior surface of a rotatingdrum (forming an enclosure) includes recesses formed between prominencesthat extend inwardly from the interior surface. The recesses are adaptedand configured to be filled or partially filled with solid CO₂ from oneor more liquid CO₂ nozzles disposed within the enclosure that injectsolid CO₂ towards the interior surface. In the event that solid CO₂ issublimated or tumbles out of recesses in portions of the drum rotatingoverhead, a depth of solid CO₂ is replenished by injection of the solidCO₂ from the nozzle(s). Typically, the solid CO₂ is deposited into theempty or partially empty recesses prior to that portion of the innersurface passing under the objects tumbling inside the rotating drum. Inthis way, the depth of solid CO₂ in empty or partially empty recesses isreplenished and the objects to be cooled or frozen at most only touchthe innermost portions of the prominences. Thus, the problem ofproduct/drum sticking that is experienced by conventional apparatusesand methods is reduced or avoided.

Alternatively, or in addition to the above-described solid CO₂ depthreplenishment or partial replenishment, the nozzle(s) may deposit afresh layer of solid CO₂ on top of the objects tumbling at or adjacentto a bottom of the rotating drum. When combined with the above-describedCO₂ depth replenishment or partial replenishment, each of the opposingsurfaces of the objects are in direct contact with solid CO₂ so that theefficiency of the cryogenic cooling is enhanced in comparison toconventional apparatuses and methods.

The solid CO₂ that is deposited into empty or partially empty recessesis injected by at least one first liquid CO₂ nozzle and the solid CO₂that is deposited on top of the objects is injected by at least onesecond liquid CO₂ nozzle. Each of the at least one first liquid CO₂nozzle is adapted, configured and oriented to inject a first stream ofsolid CO₂ towards a first angular position on the interior surface whileeach of the at least one second liquid CO₂ nozzle is adapted, configuredand oriented to inject a first stream of solid CO₂ towards a secondangular position on the interior surface. The first angular position isgenerally around a one quarter revolution of the drum from a top of thedrum while the second angular position is generally around a halfrevolution of the drum from a top of the drum. Typically, the firstangular position is between 50-130° or 230-310° (or in the case of twofirst liquid CO2 nozzles at a same axial position of the drum, between50-130° and between 230-310°) with respect to vertical. Typically, thesecond angular position is between 140-220° with respect to vertical.More typically, the first angular position is between 80-120° withrespect to vertical and the second angular position is between 160-200°with respect to vertical.

Solid CO₂ has a significant latent heat of vaporization. When heat istransferred from the object (to be cooled or frozen) to the solid CO₂,an amount of the solid CO₂ is sublimated. Solid CO₂ at atmosphericpressure is at a temperature of around −78.5° C. When the objects to becooled or frozen are food products, the liquid CO₂ injected from thenozzle(s) is typically food-grade CO₂.

The rotatable drum may have any shape that permits rotation, includingbut not limited to cylindrical, a hexagonal prism (i.e., elongatedhexagon), or an octagonal prism (i.e., elongated octagon). Typically, itis cylindrical. The axis of the rotatable drum is generally positionedmore horizontal than vertical. Typically, the drum axis is declined fromthe inlet towards the outlet in order to move the objects from the inletto the outlet by the force of gravity. The interior surface of therotatable drum is polyethylene, typically food-grade polyethylene.Polyethylene exhibits much less sticking between it and the objects tobe cooled in comparison to conventional drum materials such as stainlesssteel.

The drum has prominences extending inwardly from the inner surface.Recesses are formed between the prominences. Solid CO₂ injected by theone or nozzles fills or partially fills these recesses with CO₂ snow. Inthis manner, a portion of the surface of the object adjacent the innersurface of the drum is in contact with solid CO₂ (filling or partiallyfilling a recess) instead of with the inner surface of the drum. In thismanner, at most only a portion of each object to be chilled or frozen isin direct contact with one or more prominences. Thus, the problem ofsticking exhibited by conventional apparatuses and methods is reduced oravoided. It should be noted that the inner surface of the drum iscontinuous and not perforated, so that the solid CO₂ may not passthrough the drum in the radial direction.

The particular shape of the prominences is not essential to theinvention so long as the prominences are sized and spaced to formvalleys that can be filled with CO₂ snow to cool or freeze objectsextending across them or suspended on the prominences. The desired shapeof the prominences is typically driven by the ease with which the shapesmay be manufactured, such as by molding, and/or is driven by the shapeand size of the object to be cooled or frozen. While the shapes of eachof the prominences need not be uniform, typically they are. Similarly,while the spaces in between the prominences need not be uniform,typically they are.

By way of a non-limiting example, in the case of meat products to bechilled or frozen, the heights of the prominences typically extendapproximately 0.25 inches to approximately 1 inch from the interiorsurface of the drum. However, one of ordinary skill in the art willrecognize that for larger or smaller objects, the heights of theprominences may respectively extend a longer or shorter distance fromthe interior surface. One of ordinary skill in the art will of courserecognize that the depth of a particular recess will equal the height ofan adjacent prominence. Thus, for prominences having heights of 0.25inches or 1 inch, the corresponding recesses have depths of 0.25 inchesor 1 inch, respectively. Consequently, the solid CO₂ filling the recessin the foregoing example will have a fill depth of 0.25 inches to 1inch.

The prominences may be cylindrically shaped so that each portion of aplanar, circular top surface of the prominence extends a same heightfrom the interior surface of the drum. Alternatively, the prominencesmay be hemispherically shaped so that the height of the prominence is ata minimum at its outer circumference and is at a maximum in the centerof the prominence. While an outer edge of each cylindrical orhemispherical projection is typically located approximately 0.25 inchesto 2.00 inches from the outer edges of adjacent cylindrical orhemispherical prominences, this prominence-to-prominence spacingdistance may be greater or smaller depending upon the size of the objectto be chilled or cooled.

The cross-sectional shape of the prominences (taken along a height ofthe prominences) may take include: crescent moons, semicircles, ovals,rectangles, parallelograms, trapezoids, crosses, triangles, squares,pentagons, hexagons, heptagons, octagons, and the like. Combinations ofthese shapes may also be used.

The prominences may also be shaped as parallel ridges. The heights ofthe ridges and the spacing in between adjacent ridges are not limitedand may be varied upon the size and shape of the object to be cooled orfrozen. The parallel ridges may be oriented parallel to the axis of thedrum, perpendicular to the axis of the drum, or angled to the axis ofthe drum. Alternatively, the parallel ridges may be oriented such thatthey form spirals with an axis of the spiral being the axis of the drum.In this way, the spiral-oriented parallel ridges form “rifling” thathelps move the object (to be chilled or frozen) along the axis of thedrum from the inlet to the outlet.

The prominences are not directional vanes, but instead are positioned tosuspend the object away from the interior surface. Directional vanes arecommonly used in rotatable drums to direct the object from the inlet tothe outlet during rotation. Directional vanes can further bedistinguished from the prominences of the invention by the fact thatdirectional vanes have a height dimension (in the radial directionextending inward towards the axis of the drum) that is at least threetimes greater than its width dimension, while the prominences of theinvention do not. Because the directional vanes have such a high aspectratio (height to width), they are very poorly suited to contain a depthof solid CO₂ in between the vanes. In other words, the relatively highheight of the vanes results in a relatively great depth of solid CO₂that may tend to accumulate in between the vanes. The relatively greaterdepth and corresponding mass of solid CO₂ will greatly increase theenergy needed to rotate the drum. Additionally, the high aspect ratioand corresponding greater surface area will increase the extent to whichthere is direct contact between a chilled vane and a substantial portionof a surface of the object to be cooled or chilled. One of ordinaryskill in the art will recognize that these disadvantages of directionalvanes do not solve the problem of product/drum sticking exhibited byconventional apparatuses and methods. Nevertheless, the disclosedapparatus may include some amount of directional vanes in addition tothe prominences.

As best illustrated in FIG. 1, the objects 11 to be cooled or chilledare introduced into the inlet of the drum 12 and the drum 12 is rotated.

Solid CO₂ may be injected towards the inner surface 9 of the drum 12from one or more first liquid CO₂ nozzle 34′, 34″ to produce a blanketof solid CO₂ snow 21 on the inner surface 9 between the prominences 38.The liquid CO₂ is introduced to the nozzle 34′, 34″ via a header 13. InFIG. 1, the first liquid CO₂ nozzle 34′ may be oriented to inject astream of solid CO₂ at a first angular position of the drum 12,generally between 50-130° or the first liquid CO₂ nozzle 34″ may beoriented to inject a stream of solid CO₂ at a converse first angularposition of the drum 12 between 230-310° with respect to vertical.Alternatively, each of the first liquid CO₂ nozzles 34′, 34″ may beutilized, one of which injects a stream of solid CO₂ to a first angularposition between 50-130° with respect to vertical and the other of whichinjects a stream of solid CO₂ to a converse angular position between230-310° with respect to vertical.

As the drum 12 rotates (assuming for the sake of argument, in theclockwise direction), the gravity causes the objects 11 to tumbledownwardly from the prominences 37 and solid CO₂ 21 in the recessesformed between the prominences 37 from the “left” side of the drum (forexample, just short of 270°) towards the bottom of the drum 12 (forexample, at around 180°) as that side is rotated upwardly towards a top(for example, at around 0°) of the drum 12. The drum 12 may be rotatedin either clockwise or counter-clockwise direction and one of ordinaryskill in the art will recognize that the angular positions describedherein may be adjusted to account for any change in rotationaldirection. After the object 11 has tumbled away from that side of thedrum 11, solid CO₂ 21 is freshly deposited in the recesses of a portion(for example, at around 270°) of the drum 12 that is being rotatedupwardly from a bottom of the drum 12 to a top of the drum 12.Alternatively (or in addition to the deposition of snow at around 270°),the solid CO₂ 21 is freshly deposited in the recesses of a portion (forexample, at around 90°) of the drum 12 that is being rotated downwardlyfrom a top of the drum to a bottom of the drum 12. In this manner, solidCO₂ that is diminished through sublimation or which is jarred loose bybumping of the objects or which falls out of recesses by the force ofgravity may be replenished or partially replenished in the recesses thatare empty or partially empty. As a result, a substantial area of theinner surface 9 of the drum 12 is separated from the objects 11 by alayer of solid CO₂ 21.

A stream 38 of solid CO₂ may also be injected by a second liquid CO₂nozzle 36 to produce a blanket of solid CO₂ (not shown) on top of theobject 11. The second liquid CO₂ nozzle 36 may also be used inconjunction with one or both of the first liquid CO₂ nozzles 34′, 34″.This allows each opposing layer of the object 11 to be cooled or frozenby contact with solid CO₂ 21. In other words, the object 11 issandwiched between the solid CO₂ 21 in the recesses and the layer ofsolid CO₂ (not shown) on top of the object 11. The combination of thetwo nozzle orientations and the prominences 37 allow both sides of theobject to contact the solid CO₂, resulting in more efficient cooling.

One of ordinary skill in the art will recognize that the schematicillustration of FIG. 1 depicts a cross-section of the invention at anaxial position of the drum 12. Typically, there are multiple firstliquid CO₂ nozzles 34′ or 34″ each one of which is oriented to inject afirst stream of solid CO₂ 35′ or 35″ at more or less a same firstangular position. Thus, there are typically multiple first streams 35′or 35″ of solid CO₂ that are parallel to, and spaced from one another inthe axial direction of the drum 12. Similarly, there are typicallymultiple second liquid CO₂ nozzles 36 each one of which is oriented toinject a second stream 38 of solid CO₂ at more or less a same secondangular position. Thus, there are typically multiple second streams 38of solid CO₂ that are parallel to, and spaced from one another in theaxial direction of the drum 12.

The objects 11 can traverse the drum 12 from an inlet to an outlet ofthe drum 12 by force of gravity caused by a declination of the drum 12from the inlet to an outlet. The objects 11 can also traverse the drum12 through the use of direction vanes (not shown in FIG. 1 that urgesthe objects 11 from the inlet to the outlet as the drum 12 is rotated.The objects 11 are then removed from the outlet of the drum 12.

As best shown in FIG. 2, the object 11 is introduced into the inlet 22of the drum 12 by a conveyor 10. One of ordinary skill in the art willrecognize that alternate methods of introduction may also be usedwithout departing from the teachings herein.

In the embodiment depicted in FIG. 2, the drum 12 is rotated by drivemotor 15 and drive wheels 16. One of ordinary skill in the art willrecognize that alternate mechanisms may be utilized to rotate drum 12without departing from the teachings herein. During rotation of the drum12, directional vanes 14 move the object 11 from the inlet 22 to theoutlet 23.

In the embodiment depicted in FIG. 2, the chilled or frozen object 11exits the outlet 23 of the drum 12 via buckets 17 (in a way well knownto those skilled in the art of material handling) and discharge slide18. One of ordinary skill in the art will recognize that alternateoutlet mechanisms may be utilized without departing from the teachingsherein.

In the embodiment depicted in FIG. 2, liquid CO₂ 20 is introduced vialiquid CO₂ injection header assembly 13 and nozzles 22 a and 22 b. Theliquid CO₂ 20 is expanded to solid CO₂ 21 at nozzles 22 a and 22 b.Exhaust ducts 19 prevent the CO₂ gas from the escaping from drum 12 intothe atmosphere.

As best illustrated in FIG. 3, the object 11 (not shown in FIG. 3) isintroduced into the inlet 22 of the rotating drum 12 and removed fromthe outlet 23. Cutaway portion 24 of rotating drum 12 provides furtherdetail in FIGS. 4-6 of the interior surface 25 of the rotating drum.FIGS. 4-6 are not drawn to scale.

As best shown in FIG. 4, one embodiment of the interior surface 25 ofrotating drum 12 includes prominences 37 having a cylindricalconfiguration. The cylindrical prominences 37 extend approximately 0.5inches from the interior surface 25 as shown by line z₁ to z₂ (height).Without limiting the scope of the invention, the diameter of thecylindrical prominence 37 can be approximately 1 inch as shown by linex₁ to x₂ and the distance between cylindrical prominences 37 can beapproximately 1 inch as shown by line x₃ to x₄.

As best illustrated in FIG. 5, the prominences 26 are hemispherical. Thehemispherical prominences 37 extend approximately 0.5 inches from theinterior surface 25 to its apex as shown by line z₁ to z₂ (height). Thediameter of the hemispherical prominence 26 at its base is approximately1 inch as shown by line x₁ to x₂. The distance between hemisphericalprominences is approximately 1 inch as shown by line x₃ to x₄.

As best shown in FIG. 6, the prominences 37 have a ridge configuration.The ridged prominences 37 extend approximately 0.5 inches from theinterior surface 25 to its apex as shown by line z₁ to z₂ (height). Thedistance between ridged prominences is approximately 2 inches as shownby line x₃ to x₄. The ridged prominences 26 are approximately 0.5 incheswide as shown by line x₁ to x₂. The length of the ridged prominences 37can vary from as much as one full revolution of the inner surface of thedrum 12 to any fraction of one full revolution. The ridged prominences37 may extend around the inner surface at a same axial distance along anaxis of the drum 12. Alternatively, they may be formed as a single helixor as parallel helices. One of ordinary skill in the art will recognizethat, depending upon the orientation of the ridged prominences 37, thelength (y₁-y₂) may equal or exceed the circumference of the rotatingdrum 12.

One of ordinary skill in the art will recognize that other shapes and/orgreater or smaller diameters or widths (x₁-x₂) or lengths (y₁-y₂) orheights (z₁-z₂) of the prominences 37 or distances (x₃-x₄) between theprominences 37 may be used without departing from the scope of thisinvention. As discussed above, the diameter and/or height of theprominences 37 is typically driven by the ease with which they may bemanufactured or by the shape and size of the object 11 to be cooled orfrozen. Furthermore, one of ordinary skill in the art will recognizethat uniformity amongst the prominences is not required to practice theteachings of the disclosed method and apparatus and that variation ofshape, width, length, height, and distance may occur within one drum 12.

It will be understood that many additional changes in the details,materials, steps, and arrangement of parts, which have been hereindescribed and illustrated in order to explain the nature of theinvention, may be made by those skilled in the art within the principleand scope of the invention as expressed in the appended claims. Thus,the present invention is not intended to be limited to the specificembodiments in the examples given above and/or the attached drawings.

What is claimed is:
 1. An apparatus for chilling or freezing objects,the apparatus comprising a rotatable drum defining an enclosure havingan interior surface, an inlet at one end of the drum, an outlet at anopposing end of the drum, one or more liquid CO₂ nozzles disposed in aninterior of the drum each one of which is adapted to inject a stream ofsolid CO₂ into the enclosure towards the interior surface, wherein: theinterior surface of the drum is comprised of polyethylene havingprominences molded into the polyethylene; portions of the interiorsurface in between prominences form recesses relative to the prominencesthat are adapted and configured to retain a depth of solid CO₂; and theprominences are not directional vanes.
 2. The apparatus of claim 1,wherein: said at least two liquid CO₂ nozzles comprise at least onefirst liquid CO₂ nozzle and at least one second liquid CO₂; each of saidat least one first liquid CO₂ nozzles being disposed in an interior ofthe drum and being adapted, configured, and oriented to provide a firststream of solid CO₂ towards a first angular position on the innersurface; each of said at least one second liquid CO₂ nozzle beingdisposed in the drum interior and being adapted, configured, andoriented to provide a second stream of solid CO₂ towards a secondangular position on the inner surface; and the first angular position isbetween 70-110° and/or 250-290° with respect to vertical and the secondangular position is between 160-200° with respect to vertical.
 3. Theapparatus of claim 1, further comprising directional vanes on theinterior surface.
 4. The apparatus of claim 1, wherein the prominencesextend approximately 0.25 to 1 inches from the interior surface.
 5. Theapparatus of claim 4, further comprising directional vanes on theinterior surface.
 6. A method for chilling or freezing objects,comprising the steps of: providing the apparatus of claim 1; rotatingthe drum; introducing the objects into the interior the drum; andinjecting a stream of solid CO₂ into the enclosure towards the interiorsurface from one or more liquid CO₂ nozzles, wherein the solid CO₂ isdeposited in the recesses and/or on top of the objects; and removing theobjects from the outlet of the drum.
 7. The method of claim 6, wherein:said at least two liquid CO₂ nozzles comprise at least one first liquidCO₂ nozzle and at least one second liquid CO₂; each of said at least onefirst liquid CO₂ nozzles being disposed in an interior of the drum andinjects a first stream of solid CO₂ towards a first angular position onthe inner surface; each of said at least one second liquid CO₂ nozzlebeing disposed in the drum interior and injects a second stream of solidCO₂ towards a second angular position on the inner surface; and thefirst angular position is between 70-110° and/or 250-290° with respectto vertical and the second angular position is between 160-200° withrespect to vertical.
 8. The method of claim 7, wherein the firststream(s) deposits a fresh layer of solid CO₂ in the recesses and thesecond stream(s) deposits solid CO₂ on top of the objects tumbling at oradjacent to a bottom of the drum.
 9. The method of claim 6, wherein theobjects are food products.
 10. The method of claim 9, wherein the foodproducts are meat products.